In recent years, many mobile terminals, such as cellular phones, and home information appliances such as BD (Blu-ray Disc) recorders have an interface that can access an external medium, such as a memory card. The capacity and access speed of all external media, including memory cards, have continued to increase, and external media that have attained a transfer rate of 90 MB/s are now commercially available.
An interface that accesses such an external medium typically uses a wired connection, although wireless connection is also used.
One way of detecting an external medium during wireless connection is to use a proximity sensor, such as an infrared sensor (for example, see Patent Literature 1). The non-contact card recognition device in Patent Literature 1 uses an infrared sensor to detect that a non-contact card is in the proximity of the non-contact card recognition device.